Thread pull-offs



April 22, 19.69 w. E. PATRICK ET AL 3,439,639

THREAD PULL-oFFs Filed. ont. 16. 196? Sheet Q mm mm mm/ @n n @m Nw INVENTORS E. Patrick and Fennesz Jr.

wmicm Frank April 22, 196,9 w, E, PATRlCK ET AL THREAD PuLL-oFFs sheet 2 -ofs' Filed OC#- 16, 19.67

INVENTORS William E. Patrick and Frank Fennesz Jr. BY Y TTORNEY April 22, 1969 w. E. PATRICK ET AL -THREAD PULL-oFFs Filed oct. 16. 1967 sheet .5 afs,

\ i 11?. ii 32 3 v INVENTORS l y William E. Patrick and .Frank Fennesz Jr.. Wnness v 38 33 59 i 55 57 BY a lg Se .@,/ul W -AT oRNEY United States Patent O 3,439,639 THREAD PULL-OFFS William E. Patrick, Brighstone, England, and Frank Fennesz, Jr., Clark, NJ., assignors to the Singer Company, New York, N.Y., a corporation of New Jersey Filed Oct. 16, 1967, Ser. No. 675,558 Int. Cl. D051! 49/00, 3/02 U.S. Cl. 112-242 2 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention The invention relates to pull-offs for compensating looper zig-zag mechanisms.

Description of the prior art The most prevalent type of compensating loop taker is one which pivots on a horizontal axis and is oscillated laterally to compensate for lateral oscillation of a needle. In prior horizontal axis compensating loop takers, thread pull-olf occurs only before leftmost needle penetrations as viewed from the front of the machine. As the loop taker shifts laterally to the left to compensate for lateral oscillation of the needle, the top of the loop taker bears against thread between the loop taker and an article to be sewn to pull off thread from a thread supply in the loop taker. However, as the loop taker shifts laterally to the right, the top of the loop taker 'does not bear against the thread between the loop taker and the article to be sewn because of the adverse angle of the thread. Therefore, there is no thread pull-off before the rightmost needle penetrations and, consequently, uneven stitches result. Since the leftmost needle penetrations thus have slack thread available while the rightmost needle penetrations do not, the loop taker thread is pulled by the takeup through to the top of the article being -sewn after the leftmost penetrations but not after the rightmost needle penetrations. The Iuneven stitches look especially bad if the loop taker thread is a different color than the needle thread.

SUMMARY OF THE INVENTION It is therefore a primary object of the invention to provide an improved thread pull-off for compensating horizontal -aXis loop takers in -which substantially equal lengths of thread are pulled olf from a thread supply in the loop taker for both leftmost and rightmost penetrations of the needle.

Another object of the invention is to provide a thread pull-olf in accordance with the foregoing object i-n which a larger loop of needle thread is formed for the loop taker, and the loop taker thread is held upstream from the needle relative to normal movement of an article to be sewn to eliminate the possibility of half hitch stitches and to provide a uniform orientation of the loop taker thread.

Other objects and a fuller understanding of the invention may :be had by referring to the description and claims taken in conjunction 'with the accompanying drawings.

ICC

BRIEF DESCRIPTION yOF THE DRAWINGS FIG. 1 is a longitudinal cross sectional view of a sewing machine incorporating the invention;

FIG. 2 is a head end elevational view of the oscillating shuttle of the sewing machine of IFIG. 1;

FIG. 3 is a top plan detail view of the oscillating shuttle;

FIG. 4 is a perspective view of the thread pull-off;

FIG. 5 is a detail longitudinal cross sectional view of the oscillating shuttle in rightmost position; and

FIG. 6 is a detail longitudinal cross sectional view of the oscillating shuttle in leftmost position.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings, the invention is illustrated embodied in a sewing machine havin-g a frame including a Work supporting bed 11, a hollow standard 12 rising from one end of the bed, a hollow bracket arm 13 at the top of the standard overhanging the bed, and a sewing head 14 at the free end of the bracket arm. A throat plate 15 having a needle aperture 16 is mounted on the work supporting bed.

Mounted in the sewing head is a needle drive mechanism indicated generally at 17, and mounted in the hollow bracket arm is a needle jogging mechanism indicated generally at 18. A compensating loop taker indicated generally at 19 is mounted in the bed.

The needle drive mechanism includes a needle bar gate 20 which is pivotally mounted in the sewing head on a hinge pin 21. A needle bar 22 is mounted on the needle bar gate, and a needle 23 is connected to the end of the needle bar. vEndwi-se reciprocation is imparted to the needle bar by a crank 24 on the end of an arrn shaft 25 journaled in the bracket arm. A link 26 is pivotally connected between a crank pin 27 on the crank and a lateral pin 28 on a clamp 29 on the needle bar. The arm shaft is rotated through a handwheel 30 on the standard end of the arm shaft. Lateral oscillation is imparted to the needle bar gate 20 and hence tothe needle by a connecting rod 31 which is connected between the needle bar gate and the needle jogging mechanism 18.

The compensating loop taker 19 is mounted on the end of ya bed shaft 32 journaled in the bed. The compensating loop taker includes a housing 33 journaled on the bed shaft and a loop taker in the form of an oscillating shuttle 34 connected to the end of the bed shaft. The shuttle has a loop-seizing beak 35. A bobbin case 36 is mounted in the `shuttle and a bobbin 37 is mounted in the :bobbin case. A shuttle cap 38 is hinged on the end of the loop taker housing by a hinge pin 39 and is held in a closed position by a latch 40 pivotally mounted on the loop taker housing by a pivot screw 41.

AOscillating motion is imparted to the shuttle 34 by a vertical pitman 42 in the standard. The vertical pitman has a fork 43 at the top which embraces an eccentric 44 on the arm shaft. At the bottom, the vertical pitman is connected to a crank 45 on the bed shaft through a series of rock arms indicated generally at `46. A finger 47 on the bobbin case 36 seats in a notch 48 in the shuttle cap 3'8 to prevent rotation of the bobbin case.

Lateral oscillation is imparted to the compensating loop taker bya second connecting rod 49 pivotally connected to the needle bar gate 20. The other end of the second connecting rod is pivotally connected to a rock arm on a vertical rock shaft 50 in the standard. The rock arm is not shown.'A roller 51 on a second rock arm 52 at the bottom of the vertical rock shaft in the standard rides between two iianges 53 and 54 on the bed shaft to transmit lateral oscillation to the bed shaft and hence to the compensating loop taker in timed relation with lateral oscil- 9 lation of the needle bar gate and hence the needle. A slide pin 55 held in a bore 56 in a front leg 57 of the sewing machine by a setscrew 58 seats in a groove 59 in the loop taker housing to prevent rotation of the loop taker housing while permitting lateral oscillation of the loop taker housing.

Mounted on top of the loop taker housing is a thread pull-off indicated generally at 60. The thread pull-oft" includes mounting bracket 61 having two holes 62 and 63. The mounting bracket is connected to the top of the loop taker housing 33 by two screws 64 and 65 which extend through the holes 62 and 63 in the mounting bracket. Extending rearwardly from the mounting bracket is finger 66. A vertical L-shaped lug 67 having a proximal portion 68 and a distal portion 69 is formed at the free end of the finger with the distal portion 69 substantially perpendicular to normal movement of an article 70 to be sewn on the work supporting bed. A hook 71 depends from the distal portion of the L-shaped lug. The proximal portion 68 is approximately 1&4 of an inch from the left side of the needle.

In operation, with particular reference to FIG. 5, before a rightmost penetration of the needle, the needle and compensating loop taker 19 shift to the right. Thread 72 between the bobbin 37 and the article 70 to be sewn is held in the dihedral angle formed by the proximal and distal portions 68 and 69 of the vertical L-shaped lug 67 of the thread pull-off 60. Movement of the thread pullolf to the right with the compensating loop taker pulls off thread from the bobbin for the rightmost stitch.

With particular reference to FIG. 6, before a leftmost penetration of the needle, the needle and compensating loop taker shift to the left. The thread between the bobbin and the article to be sewn is held in the angle formed by the distal portion 69 of the vertical L-shaped lug and the hook 71 which depends from the distal portion of the vertical L-shaped lug. Movement of the thread pull-off to the left with the compensating loop taker pulls olif thread from the bobbin for the leftmost stitch. The pull off of thread for the leftmost stitch is substantially equal to the pull off of thread for the rightmost stitch.

Without the thread pull-off, the thread between the bobbin and the article to be sewn was held by the bottom of the needle aperture 16 in the throat plate 15. With a thread pull-off, the thread is held by the bottom of the vertical L-shaped lug 67. The vertical L-shaped lug holds the thread closer to the needle, and hence a larger loop of needle thread 73 can be formed for the loop-seizing beak 35 of the shuttle 34. In addition, since the vertical L-shaped lug of the thread pull-off holds the thread upstream relative to the normal movement of the article to be sewn, the possibility of half hitch on skipped stitches is eliminated, and a uniform orientation of the bobbin thread for each stitch is obtained.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

Having thus set forth the nature of the invention, what is claimed is:

1. A thread pull-olf for a sewing machine having a frame, a needle bar mounted in the frame, a thread-carrying needle xed in said needle bar, means for imparting endwise reciprocation to the needle bar, means for imparting lateral oscillation to the needle bar, a housing for a loop taker mounted in the frame, a horizontal axis loop taker having a thread supply mounted in the loop taker housing for cooperation with the needle on the needle bar, means for imparting motion to the loop taker in timed relation with endwise reciprocation of the needle bar to form stitches in an article to bc sewn, and means for imparting lateral oscillation to the loop taker in timed relation with lateral oscillation of the needle bar, said thread pull-oit comprising a mounting bracket, a finger extending from the mounting bracket, and means for mounting the mounting bracket on top of the loop taker housing for lateral oscillation with the finger extending downstream relative to the normal movement of the article to be sewn and in the path of thread between the thread supply of the loop taker and the article to be sewn, a substantially vertical L-shaped lug formed on the free end of the finger with the distal portion of the L-shaped lug upstream relative to the normal movement of the article to be sewn and substantially perpendicular to the normal movement of the article to be sewn to pull off thread from the thread supply of the loop taker, and a hook formed on the distal portion of the L-shaped lug to retain thread on the finger.

2. A thread pull-off as set forth in claim 1 in which said substantially vertical L-shaped lug at the free end of the linger is formed with a substantially longitudinal proximal portion and a substantially transverse distal portion defining a dihedral angle for holding thread when the loop taker is laterally oscillated in one direction and in which said hook depending from the distal portion of the L-shaped lug denes a second angle for holding thread when the loop taker is laterally oscillated in the other direction.

References Cited UNITED STATES PATENTS 432,449 7/1890 Stewart ll2-159 621,170 3/1899 Stewart 112-159 1,385,048 7/1921 Herr 112-159 2,43 8,833 3/1948 Wood 112-242 2,877,725 3/1959 Ioannilli 112-58 XR 3,009,433 ll/l961 Kuhn 112-219 RICHARD I. SCANLAN, JR., Primary Examiner.

U.S. Cl. X.R. 112-159 

